Patient chair



C. S. DAVIS PATIENT CHAIR March 26, 1963 Filed March 25. 1961 5 Sheets-Sheet 1 @lf/AMES .5i 0A l//s INVENTOR.

BY [AWT Innen/5y March 26, 1963 c. SDM/1s 3,083,055

PATIENT CHAIR Filed March 23. 1961 5 Sheets-Sheet 2 BY wwwma- C. S. DAVIS PATIENT CHAIR March 26, 1963 3 Sheets-Sheet 3 Filed March 23, 1961 CHA @L E5 5. DA ws IN V EN TOR.

,4 from/E Y United States Patent O 3,033,055 PATIENT CHAIR Charles S. Davis, 1815 Terri Way, San Jose, Calif. Filed Mar. 23, 1961, Ser. No. 97,875 8 Claims. (Cl. 297-345) This invention relates generally to chairs and more particularly to a chair providing for various adjustments such as variation of seat height and variation of the angle of inclination and length of the back rest.

Patient chairs areV used extensively to place patien-ts in a position to permit the attending doctor, whether he be medical or dental, to perform a Variety of different tasks such as surgical, dental treatments or operations. One of the desirable features of such a patient chair or platform is adjustability to comfortably accommodate patients of different body proportions and to allow for change of patient body position for different kinds of treatment or surgery. Also, the patient chair should permit such adjustments to enable doctors having different heights or working habits in giving treatments to do so in comfort and without undue strain. All patient chairs heretofore known have been found limited in the range of their adjustments in some respects. For example, patient chairs known heretofore have made it impossible for the attendant physician to sit with his legs extended under a reclining patient andvhave not provided back support over the entire back of the patient.

It is therefore an object of this invention to provide a patient chair having a greater range of adjustment than chairs heretofore known.

'It is a further object of this invention to provide a patient chair giving a doctor better access to the particular area of the patients body to be treated.

It is a still further object of -the invention to provide for increased vertical range of adjustment of a patient chair and to provide a back rest which fully supports the patients back at all times.

It is another object of the invention to provide a chair having a head rest always properly placed in relation to the back rest and to provide full patient comfort by having arm rests which Vadjust with change of back rest angle.

It is still another object of the invention to provide a patient chair which is simple in construction, inexpensive to manufacture and easy to maintain.

Gther objects and a fuller understanding of the invention may be had by referring to Ithe following description and claims, taken in conjunction with the accompanying drawings in which:

FIGURE 1 shows a side elevational view, partly in section, of the patient chair of this invention and includes, in phamtom view, a different position of the sea-t and the back rest;

FIGURE 2 shows a rear end view of the patient chair of FIGURE l;

FIGURE 3 shows a of FIGURE l;

FIGURE 4 shows a cross sectional view taken along the line 4 4 of FIGURE 2;

FIGURE 5 is an enlarged fragmental cross-sectional View of portion 5--5 of FIGUR-E 4;

FIGURE 6 shows a side elevational view partly in cross section of the back rest actuating means for changing the angled inclination of the back rest and the horizontal position of the arm rests of the chair of FIGURE 1;

' FIGURE 7 shows an exploded perspective View of a portion vof the telescoping assembly used in changing the length of the back rest; and

FIGURE S shows a perspective view of the arm rest assembly of the patient chair of FIGURE l.

Referring now to the drawings, in which like reference front end View of the patient chair 3,083,055 Patented Mar. 26, 1963 ICS characters designate like parts, a base assembly generally designated as 10 includes a base plate 12 having two support brackets 14 and 16 mounted to opposite sides of base plate 12. Support brackets 14 and 16 which include vertical support plates 14a, 14h and 16a, 16b resectively, and may be of unitized construction in the form of U- shaped uprights, or may be constructed by bolting or welding the vertical support plates to back plates 14C and 16C. The double construction of brackets y14 and 16 is to ensure a good support and a housing for the parallelogram linkages presently to be described.

A seat frame generally designated as 20 includes a pair of seat brackets 22 and 24 which may be inverted U- shaped sections having parallel sides. Seat frame 20 is connected to hose assembly 10 by four support arms 25, 26, 27 and 28 constituting a pair of parallelogram linkages. Each support arm has a width to iit in-to the space between the adjacent vertical support plates of support brackets y14 and 16 and the side walls of seat brackets 22 and 24 and a circular opening in each end for engagement with pivot pins, generally designated `as 30. Pivot pins 30 have their ends supported in support brackets 14 and 16 and seat brackets 22 and 24 and thereby provide rotatable engagement with the support arms. Support arms 25, 26, 27 and 28 are of equal length and are mounted parallel in pairs to provide a pair of parallelol gram linkages. It is well known that `such a support of seat frame 20 provides a motion which is purely translational and which raises seat frame y20 parallel to itself without any tilting.

Support Varms 26 and 28 are tied to one another through tie bar 32 which preferably has a circular cross section so it may be rotatably engaged with one end of a pair of thrust members 34 and 36. The other ends of thrust members 34 and 36 are connected to cross member l38 which is provided with a threaded hole 40 for engagement with a rotatably mounted threaded spindle 42.l Instead of threading a hole into cross member `38, a plain hole may be drilled and a conventional threaded nut may be welded or otherwise fastened to one of the surfaces of cross member 38. Y

Threaded spindle `42 has a large bevel gear 44 mounted to its lower end which end is also supported by a conventional thrust bearing 46. Bevel gear 44 engages a small bevel gear 48 mounted on shaft 50 of a motor 52 supported on ya base plate 12. As motor 52 rotates motor shaft 50, threaded spindle 42 will likewise rotate through engagement with gears 48 and 44. Rotation of threaded spindle 42 and its engagement with cross member 38 will raise or lower cross member 38 depending on the direction of rotation, and thereby cause rotation of support arms y26 and 28 about pins 30 supported in support brackets 14 and 16.

Such a rotation of one member of the parallelogram link- Aages causes a lowering or raising of seat frame 20. To protect motor 52 and bevel gears 44 and 43 from dust and dirt and to provide a better appearance, a motor cover 5 4 having an opening through which thrust members 34 and 36 may freely move may be used to enclose the major portion of the parallelogram linkage actuating assembly.

. The seating frame 20 is provided with a padded vand contoured seat 5'6 which may be rotatably journaled about a shaft 58 supported by seat brackets 22 and 24. Supporting seat 56 in this manner permits it to be raised for easy access to the parallelo gram linkage actuating assembly and thereby facilitate clearing and maintenance of the latter. Seat 56 is supported against rotation during normal use by a member such as shaft 66. Shafts 58 and 60l may also be utilized as spacer bars for connecting seat brackets 22 and 24 to one another in spaced relationship and to form seat frame 20 of increased rigidity.

A back rest, generally designated as 62, includes an outer support frame formed by a pair of angle brackets 64 spaanse and 66 (FIGURE 4) having respectively cylindrical bosses 68 and 70 welded or otherwise airixed to their lower ends which are rotatably journaled in a pair of bearings 72 and 74 in seat `brackets 22 and 24 respectively, Angle brackets 64 and 66 are welded or otherwise fastened to the inner angled portion of a wide U-shaped back bracket 76 (FIG- URE and form therewith the rigid outer support frame. Dimensioned for accommodation in the outer support frame is an inner support frame formed of an angle bracket 80 bent into U-shape and having Welded or otherwise affixed thereto a back rest plate 82 (FIGURES 4 and 5). Attached to back rest plate 82, preferably by Snap fasteners, is a pad 8'4 which is considerably longer than the combination of the outer and inner support frame and which folds underneath padded seat 56 as shown in FIGURE 1.

In order to provide an adjustment for lengthening back rest 62 for maximum extension, a telescoping means such as a pair of floating angle brackets 86 and 88 are disposed between adjacent sides of the inner and the outer support frame as shown in FIGURE 5. In the preferred embodiment oating angle brackets 86 and 88 are provided with a pair of long Slots (FIG. 7) for engagement with stop pin 144 anchored to bracket 76 and stop pin 146 anchored to angle bracket 80. Pins 144 and 146 are positioned in such a manner that the inner support frame may move completely into and out of the outer support member. As is well known to those skilled in the art, a second pair ofV iloating angle brackets may be provided and slotted for engagement between the inner support frame and oating angles 86 and 88 to increase the maximum extension between the inner and the outer support member still further Such arrangements are generally known as telescoping means and may also comprise an arrangement of tubes such as are often found on tripods for supporting cameras.

To supportrthe inner support frame in its position of extension, a cam lock 90 may be utilized which squeezes to end of a hollow pipe 92 fastened to the outer support member. An inner pipe or shaft 96 is dimensioned to slidably move in hollow pipe 92 and is fastened to the inner support frame by a bracket 98.V When cam lock 90 is turned to its locked position, it squeezes on shaft 96 and stops slidable motion with respect to hollow pipe 92 thereby supporting the inner support frame in its position of extension. Of course, many other means for locking the inner support frame may be used such as a locking means incorporated into the telescoping means.

Back rest 62 is held in its inclined position by a pair of tie bars 100 and 162 having one end rotatably journaled Vonra pair of cylindrical bosses or pins fixed to opposite outer sides of the outer support frame angle bracketsV 64 and 66 and above bosses 68 and 70 having the other end provided with pins 1031' for engagement with slots 103 in a pair of side plates 1-06 and 108i. Side plates 104 and 106 `are also provided with a long slot 110 dimensionedrin Width for slidable engagement with cylindrical bosses V63, 70 and shaft 58. In fact such a'slot engagement restricts side plates 4 and 106 to move horizontally'with the necessity of providing additional supports. Side plates 106 and 108 are tied together by a cross member 112 (FIG- -URES 2 and 6) which is provided with'a threaded hole 114 for engagement Witha threaded spindle 120. l Y

FIGURE 6 shows with greater particulars Vthe back rest Y inclination actuating means which comprises cross member 112 and motor driven rotatable threaded spindle 12). A

motor 116 is mounted to seat frame 120 by way of -a motor mounting plate 118lr (FIG. 1)' bolted to seat brackets 22 and 24. Mounting plate 118' also supports a thrust bearing 122 in which a threaded spindle 120 is rotatably journaled. VSince spindle 120 is being forcedforward by the Weight of a patient against back rest l62, the thrust bearing must retain spindle 120 against this force. Motor 116 and spindle V120 are connected by a gear reduction unit comprising a Vpair of gears 124 and 126, the former being the driver and the latterbeing the driven. As threaded spindlel120 is '.dotated, cross member ,171.2 is: lmoved either toward'the front or the rear of the chair imparting the same motion to side plates 106 and 108. The motion of side plates 106 land 108 is transmitted through tie bars 100 and 102 to the outer support frame to change its angle and inclination.

A head rest 131 may be attached to the top of the inner support frame, it being immediately apparent that no extendable adjustment thereof being necessary because the back rest itself may be lengthened or shortened at will. This assures that the patient is always supported along his whole back contrary to present dentist chairs, Where raising of the Vhead rest deprives a tall person of support around his shoulders.

Another feature of this invention is the movable arm rests and 132 (FIGURES 2, 3 and 8) having the shape of inverted U-shaped brackets with an additional flange portion i attached to one of the sides. Flange 150 slides on top of seat bracket 241as shown in detail in FIGURE 8. Arm rests 130 and 132 are provided with anm rest pads 101 and 1105 respectively `for patient comfort. Also arm rests 130 and 132 include vertical slots 152 (illustrated only with respect to one arm rest, the other one being of like configuration) -for slidable engage# ment with pin 103l of tie bar 100 which permits the quick removal of arm rest 132 by .merely lifting the same upwards and further positions arm rest 132 horizontally with respect to back rest 62. Slot 152 is positioned so that pad 101 of back rest 132 extends all the way to back rest 62. As the .angle of inclination of back rest 132 is changed by a forward or backward motion of side plates 106 and 10S, arm rests 1130 and 1132 being coupled to pin 1031 w-hich -form the support for movable tie 4bars 100 and 102, move along with side plates 106 and 108 and thereby insure the pad 101 and 10S moves in spaced relationship with back rest Y62.

There has been described a chair for patients which is provided with a vertical height adjustment for the seat, inclination and length adjustment for the back rest, and automatic :side adjustment for the arm rests. Further, the chair is supported entirely at its front permitting a dentist or doctor to sit in such a position that his knees are under the patients back. This is of course advantageous lfor a dentist who works on patients teeth all day long. Furthermore, the chair may be lowered more than has been possible heretofore because of .the complete absence of a conventional column such as a hydraulic lift placed centrally under the seat.

What is claimed is:

l. An adjustable chair comprising: a base plate; a seat frame; height adjustment means connecting said seat frame to said base plate for raising and lowering said seat lframe; a seat connected to said frame; and an extendable back rest including an outer support frame rotatably journ'aled at its ends tosaid seat frame, an inner support frame dimensioned for slidable receivement into said outer support frame, means for slidably connecting said inner to said outer support frame, :a pad detechably atlixed to said inner support frame, and `adjustable clamping means to secure said inner support frame in apposi- -tion of extension.

2. A patient chair comprising: a base plate for oor engagement; a seat frame; parallelogram link-age means Y connecting said seat frame to said vbase plate; actuating means mounted on said Ibase plate and connected to said parallelogram linkage means for raising and lowering said seat frame; a seatrnounted on said frame; and an extendable back rest including an outer support frame rotatably journaled at its ends to said seat frame,V `anrinner support frame dimensioned for lowering into said outer support fra-me, telescoping means for connecting said *inner to said outer support frame, a pad detaohably alixed to said inner support frame, and adjustable clamping meansV to secure said inner support frame in la position of extension.

3. A dentist and surgeon chair comprising: a base p plate of substantial length'for lloor engagement; a seat n 

2. A PATIENT CHAIR COMPRISING: A BASE PLATE FOR FLOOR ENGAGEMENT; A SEAT FRAME; PARALLELOGRAM LINKAGE MEANS CONNECTING SAID SEAT FRAME TO SAID BASE PLATE; ACTUATING MEANS MOUNTED ON SAID BASE PLATE AND CONNECTED TO SAID PARALLELOGRAM LINKAGE MEANS FOR RAISING AND LOWERING SAID SEAT FRAME; A SEAT MOUNTED ON SAID FRAME; AND AN EXTENDABLE BACK REST INCLUDING AN OUTER SUPPORT FRAME ROTATABLY JOURNALED AT ITS ENDS TO SAID SEAT FRAME, AN INNER SUPPORT FRAME DIMENSIONED FOR LOWERING INTO SAID OUTER SUPPORT FRAME, TELESCOPING MEANS FOR CONNECTING SAID INNER TO SAID OUTER SUPPORT FRAME, A PAD DETACHABLY AFFIXED TO SAID INNER SUPPORT FRAME, AND ADJUSTABLE CLAMPING MEANS TO SECURE SAID INNER SUPPORT FRAME IN A POSITION OF EXTENSION. 